In my previous two posts on the Berkeley temperature record (here and here) there was discussion of time intervals and how they influenced perceptions of temperature change.

The first graph here is what the Berkeley team released to the press. It covers the period 1800 to 2006.  The expanded Y- axis scale gives the impression of a significant recent rise in temperature.

If one looks, however, at a longer record the perception is different.  The second graph is the Central England Temperature record (CET), as far as I know, the longest  continuous instrumental record in existence. It covers the period 1659 to 2009.  Also plotted with the temperatures are carbon dioxide emissions (black line).

The impression from CET is that the temperature has risen steadily and modestly as the planet warmed up from the so-called Little Ice Age which reached its coldest around 1607.  We see within this record shorter intervals of more rapid warming and cooling.  We also see that the rapid rise of carbon dioxide emissions has had no apparent effect.

More discussion and more long temperature records from Europe can be found in this post:

A short anthology of changing climate

And for some additional perspective, the graph below, based on proxy data, shows the relative temperature for the past 10,000 years.

See also:

A Perspective on Climate Change a tutorial

Last week I wrote about Dr. Richard Muller’s BEST (Berkeley Earth Surface Temperature) program and its depiction by the press in the post Press punked by Berkeley temperature study.

Now, another voice has come forward.  The British paper Mail Online says that “Prof Judith Curry, who chairs the Department of Earth and Atmospheric Sciences at America’s prestigious Georgia Institute of Technology, said that Prof Muller’s claim that he has proven global warming sceptics wrong was also a ‘huge mistake’, with no  scientific basis.”  (See article here.)  Dr. Curry is a member of the BEST team and co-author of the four papers Dr. Muller released.

The Mail article goes on:

“In fact, Prof Curry said, the project’s research data show there has been no increase in world temperatures since the end of the Nineties – a fact confirmed by a new analysis that The Mail on Sunday has obtained.”

‘There is no scientific basis for saying that warming hasn’t stopped,’ she said. ‘To say that there is detracts from the credibility of the data, which is very unfortunate.’

However, Prof Muller denied warming was at a standstill.

‘We see no evidence of it [global warming] having slowed down,’ he told BBC Radio 4’s Today programme. There was, he added, ‘no leveling off’.

See Dr. Curry’s version of the Mail interview on her blog here.

The Mail Online article included the graph below.  The top panel shows the temperature data, which stopped in 2006, as published by Dr. Muller.  The bottom panel shows the last ten years of BEST data including 2011 so far.  The bottom panel shows a graph with level temperatures in spite of continuing increase in atmospheric carbon dioxide.

Dr. Curry, on her blog, says of the graph, “I agreed that the way the data is presented in the graph ‘hides the decline.’”

The phrase “hide the decline” refers to a now infamous part of the Climategate emails where we learned that in the construction of the Michael Mann’s “hockey stick” graph, tree ring proxy temperature data that had been used for most of the graph started to decline. It  was therefore truncated and surface temperature data was substituted in order to hide the decline and make it appear that warming was accelerating.

Dr. Curry adds in her criticism of the BEST graph, “There is NO comparison of this situation to Climategate.  Muller et al. have been very transparent in their methods and in making their data publicly available, which is highly commendable.”

Meteorologist Anthony Watts says on his blog, referring to the flatness of the temperature during the last ten years versus what was depicted on the BEST graph:

Indeed Best seems to have worked hard to obscure it. They present data covering .. almost 200 years… with a short x-axis and a stretched y-axis to accentuate the increase. The data is then smoothed using a ten year average which is ideally suited to removing the past five years of the past decade and mix the earlier standstill years with years when there was an increase. This is an ideal formula for suppressing the past decade’s data.

Watts also comments on how Muller handled the press and peer-review in the post: The BEST whopper ever.

To get the full story to date, read my last post, the Mail article, and Dr. Curry’s article, all linked above.  There are additional links of interest within Dr. Curry’s post.

I will reiterate that the BEST study dealt with only (rather unreliable) surface temperature data and does not attribute causes to temperature change.

For my perspective on climate change see:

A Perspective on Climate Change a tutorial

There is currently a raging controversy in the media about Dr. Richard Muller’s BEST (Berkeley Earth Surface Temperature) program. One point the press seems to miss is the distinction between  whether and how much warming there may have been, versus the cause of temperature change.

The Berkeley group, having noted all the charges of data manipulation in temperature databases owned by governments, both British and American, decided to redo all the temperature records.  Everyone was anxious about how they would handle the data.

The current controversy may have been precipitated by Muller, himself, with a Wall Street Journal article titled “The Case Against Global-Warming Skepticism.”

In the WSJ article Muller writes:

The temperature-station quality is largely awful. The most important stations in the U.S. are included in the Department of Energy’s Historical Climatology Network. A careful survey of these stations by a team led by meteorologist Anthony Watts showed that 70% of these stations have such poor siting that, by the U.S. government’s own measure, they result in temperature uncertainties of between two and five degrees Celsius or more. We do not know how much worse are the stations in the developing world.

Using data from all these poor stations, the U.N.’s Intergovernmental Panel on Climate Change estimates an average global 0.64ºC temperature rise in the past 50 years, “most” of which the IPCC says is due to humans. Yet the margin of error for the stations is at least three times larger than the estimated warming.

 We know that cities show anomalous warming, caused by energy use and building materials; asphalt, for instance, absorbs more sunlight than do trees. Tokyo’s temperature rose about 2ºC in the last 50 years. Could that rise, and increases in other urban areas, have been unreasonably included in the global estimates? That warming may be real, but it has nothing to do with the greenhouse effect and can’t be addressed by carbon dioxide reduction.

But then he writes:

Without good answers to all these complaints, global-warming skepticism seems sensible. But now let me explain why you should not be a skeptic, at least not any longer.

And the press frenzy began.

Much of the controversy revolves around four papers Muller released prior to formal peer-review and publication (They are still unpublished formally).  Many scientists take exception to the methodology of the BEST study, particularly how Muller averaged station temperatures, dealt with the urban heat island effect, and stated the uncertainty.  Also part of the controversy is how the data are depicted on graphs in the press.  Below are two graphs showing identical data, but the difference in the vertical temperature scale makes one look more alarming than the other:

Add to that, the land surface temperature record does not agree with the satellite record, nor is there good agreement with sea surface temperature record..  BEST uses only land-based temperature data and ignores sea surface temperature data.

Steve McIntyre, proprietor of Climate Audit noticed “BEST’s estimate of the size of the temperature increase since the start of the 19th century is much larger than previous estimates….The decade of the 1810s is shown in their estimates as being nearly 2 degrees colder than the present….It’s also interesting to interpret these results from the context of ‘dangerous climate change’, defined by the UN as 2 deg C. Under BEST’s calculations, we’ve already experienced nearly 2 deg C of climate change since the early 19th century.”  McIntyre could not replicate some of Muller’s results using raw station data.

The press, portraying Muller as a former skeptic who got religion, ran with the WSJ headline.  See, for example, an editorial by Eugene Robinson.  Robinson’s characterization of the BEST study is that it provides evidence against climate skeptics and confirms the IPCC scary scenario projections.  But ultra warming alarmist site RealClimate.org  says the BEST study is not a big deal:

Anybody expecting earthshaking news from Berkeley, now that the Berkeley Earth Surface Temperature group being led by Richard Muller has released its results, had to be content with a barely perceptible quiver. As far as the basic science goes, the results could not have been less surprising if the press release had said “Man Finds Sun Rises At Dawn.”

The whole thing boils down to what Muller said, “The temperature-station quality is largely awful.”  That means the surface temperature data is inadequate to come to any valid conclusions.  BEST measured a larger subset of the surface temperature record than some other researchers. BEST merged and “filtered” the data.  Various methods of massaging data lead to different conclusions, none of which may be close to reality.  The science is still not settled and the BEST study, despite its good intentions, provides nothing new.

See another analysis of BEST data here.